Acrylic resin has high gloss and various applications utilizing this characteristic have been developed. On the other hand, low gloss is sometimes preferred for the purpose of obtaining a composed feeling, or reducing the plastic-like quality, and the market requests low gloss products for some types of building material for outer walls, or housing for lighting.
In current gloss reducing technology, the addition of organic or inorganic gloss reducing agents and embossing process of surfaces are generally attempted.
Although inorganic gloss reducing agents such as silica and talc exist, dispersion within the resin which is the matrix, is poor, resulting in a decrease in physical property such as diminished impact resistance.
Because embossing process of surfaces is insufficient in its gloss reducing effect and is difficult in fine adjustment, ultimately its use together with gloss reducing agents is mainstream.
There are several types of organic gloss reducing agents and crosslinked polymers with an average particle diameter of a few μm to a few hundred μm are most widely used. However, it is difficult to obtain the particle diameter of a few μm to a few dozen μm, which is most effective in reducing the gloss of acrylic resin, and even when the amount added is increased, the result ends in saturation, thus falling short of the desired level.
Linear or radial structure polymers of low compatibility with matrixes may be given as other organic gloss reducing agents. The addition of styrene block copolymer such as SBS (styrene-butadiene-styrene block copolymer), SB (styrene-butadiene block copolymer) and SEBS (styrene-ethylene-butylene-styrene block copolymer), olefin rubber such as EPR (ethylene-propylene rubber) and EPDM (ethylene-propylene-diene rubber), NBR (nitrile rubber), an ionomer such as ethylene-acrylic acid (metallic salt) copolymer are known. However, they are not desirable as they bring about a decrease in physical properties such as weatherability or impact resistance.
As stated above, obtaining a low gloss effect while maintaining the physical properties is extremely difficult, and in present conditions, a low gloss acrylic resin which can sufficiently meet the market's demands does not exist.
The present invention provides an acrylic resin with excellent low gloss in addition to impact resistance, weatherability, and processability, which was not possible from prior arts, due to the aforesaid conditions.